FYI, I just got the "insert correct SD card" error message a little into the OS upgrade, and I'm pretty sure it was caused by the cheap USB SD card reader that I have. I tried it twice on the cheap card reader (including a full format on the second attempt) and it failed both times at about 3%. I then decided to try the same SD card on a laptop with a built-in card reader, and it worked on the first try.